All chairs have 2 cases: external and internal. The outer case is removable, some cases can be washed in a washing machine. As a filler seats - light small balls of expanded polystyrene foam. Balls have unique properties. Thanks to them, the chair-bag can take an arbitrary shape under the human body, perfectly adapting to its relief, be it a small child or an adult of sufficiently large size and weight! Very comfortable, stylish and ergonomic chair! Excellent addition to any interior and event!